Briefly described, the present invention, in one preferred embodiment thereof, comprises a method and apparatus for detecting tampering with a Key Track system through attempted removal of a tracked object from its ID card. In the preferred embodiment, the object is a key, but may also be other types of objects trackable with a Key Track system as detailed below. In its broadest sense, the apparatus comprises a tether made of a conducting or resistive material and attaching the key to its key card. The tether forms a conducting or resistive loop through which a current can flow when the tether is intact. In one embodiment, the touch memory device or RF tag communicates to the system controller directly through the tether loop. In another, the current flowing through the tether and consequent voltage drop across the tether is monitored by a microcontroller fixed to the ID card.
In the case of a tether loop through which the ID device communicates directly, if the tether loop is cut to remove the key, or of the card is cut, the ID device ceases to communicate with the controller. The controller logs this as the key card having been removed from the system. Since the user who tampered with the system entered his or her authorization code to access the drawer, the perpetrator will be isolated and identified at a later time when the missing key is noticed. Thus, tampering is detectable and, consequently, deterred by the system.
In an alternate and more robust embodiment of the invention, the tether contains a resistive core and a microcontroller on the key card constantly monitors a voltage drop across the tether. If the resistance changes because the tether is cut, shunted, or damaged, the microcontroller notes the event and can report a suspicious condition immediately to the central controller. The controller can then issue appropriate alarms and alert security personnel. This embodiment is an improvement over the simple conducting tether because it eliminates the delay between the tampering and its detection and also eliminates the need for a human to notice the missing key.
The invention also includes stainless or hardened key shrouds for preventing a would be thief from cutting a key directly to remove it from its tether while leaving the tether intact. A further implementation of the invention comprises a bag for containing an object to be tracked. The bag is formed with a conductive or resistive mesh, preferably embedded within the material of the bag. The mesh is defined by a strand of material that is formed into the crisscrossing pattern of the mesh and has two ends. The bag is closed and sealed by a hinged seal, which carries a touch memory or other ID device and that has contacts that engage the two ends of the mesh strand. The seal is insertable in a receptacle of a Key Track system in the usual way. If the bag is cut, the continuity of the mesh is destroyed and this event is detected and conveyed to the central controller for alarm generation. Thus, the object in the bag is secured against being cut from the bag and taken from the Key Track system. Other variations of the invention are also envisioned, as described in more detail below.
Thus, an apparatus and method is now provided that successfully addresses a vulnerability of the basic Key Track system by effectively and reliably detecting and preventing attempts to defeat the system by cutting a key or other object from its key card. In some embodiments, the invention is readily usable with the basic existing Key Track system. In other embodiments, tampering is detected immediately and appropriate alarms are sounded. These and other features, objects, and advantages of the invention will become apparent upon review of the detailed description set forth below when taken in conjunction with the accompanying drawings, which are briefly described as follows.